Following the proposal in [1]} for deriving the linearised
\({\cal N}=0\)  supergravity theory as the convolution product of
two copies of linearised Yang-Mills, we begin by reviewing the BRST
formulation for the linearised Yang-Mills theories. Thus we begin
with the Lagrangian
\({\cal L}_A = {\rm tr\,}\Big ( -{\textstyle {\frac{\scriptstyle 1}{\scriptstyle 4} } } F^{\mu \nu }\, F_{\mu \nu } +{\frac{1}{\xi }}\, ({\partial }^\mu A_\mu )^2 -\bar{c}\,\square c\Big )\,,\) 
